As the consumer's interest in information displays is growing and the demand for portable (mobile) information devices is increasing, research and commercialization of light and thin flat panel displays (“FPD”) has increased. Flat panel displays may replace the Cathode Ray Tube (“CRT”), which is the most common existing display device.
The liquid crystal display (“LCD”) is a FPD device for displaying images by using optical anisotropy of liquid crystal. LCD devices exhibit excellent resolution and color and picture quality, and as a result, they are widely applied for notebook computers or desktop monitors, and the like. In general, in the LCD device, a data signal according to image information is separately supplied to liquid crystal cells arranged in a matrix form and light transmittance of the liquid crystal cells is controlled for displaying the desired image.
The LCD device will now be described in detail with reference to FIG. 1. FIG. 1 is an exploded perspective view showing the structure of a general related art LCD device. As shown in FIG. 1, the LCD device includes a color filter substrate 5, namely, a first substrate, an array substrate 10, namely, a second substrate, and a liquid crystal layer 30 formed between the color filter substrate 5 and the array substrate 10. The color filter substrate 5 includes a color filter (C) comprising sub-color filters 7 for implementing red (R), green (G) and blue (B) color, a black matrix 6 for discriminating the sub-color filters 7 and blocking light transmitted through the liquid crystal layer 30, and a transparent common electrode 8 for applying a voltage to the liquid crystal layer 30.
The array substrate 10 includes gate lines 16 and data lines 17 which are arranged on the substrate 10 and define pixel regions P. A thin film transistor (“TFT”) T, a switching element, is formed at respective crossings of the gate lines 16 and the data lines 17, and a pixel electrode 18 is formed at each pixel region P. The pixel region P is a sub-pixel corresponding to one sub-color filter 7 of the color filter substrate 5, and a color image is obtained by combining three types of red, green and blue sub-color filters 7. Namely, the three red, green and blue sub-pixels form a single pixel, and the TFTs are connected with the red, green and blue sub-pixels.
The fabrication process of an LCD device may be divided into an array process for forming the switching elements on the array substrate and a color filter process for forming the color filters. When the array substrate and the color filter substrate are fabricated through the array process and the color filter process, they are attached through a cell process to complete a liquid crystal display panel. The cell process does not include a process that is repetitive as compared with the array process and the color filter process. The cell process may be divided into an alignment film forming process for alignment of liquid crystal molecules, a cell gap forming process, a cutting process and a liquid crystal injection process. The liquid crystal display panel fabricated through the above processes is screened through an inspection. When the liquid crystal display panel is determined to be good, polarization plates are attached on outer sides of the liquid crystal display panel and a driving circuit is connected thereto to complete the LCD device.
In the above-described inspecting process of the LCD device, a test pattern is displayed on the screen of the liquid crystal display panel to check whether there are any defective pixels. When a defective pixel is found, a repairing process is performed. Defects of the LCD device may include a color deficiency of any of the pixels, a point defect such as spots (in a continuous ON state) or dark points (in a continuous OFF state). Additional defects may be a short circuit or opening between adjacent interconnections, a line defect caused by a breakdown of a switching element due to static electricity, and the like. Specifically, a disconnection of a data line is a line defect. In the case of a point defect, it may be tolerated to a degree depending on its distribution, number and type, but in the case of a line defect, even one line defect is too critical. A line defect significantly impairs the quality of the display and its inclusion would result in a loss of value of the product.
In this case, if a pixel electrode overlaps a data line or is formed near a data line to improve the aperture ratio, parasitic capacitance may be generated between the data line and the pixel electrode. Then, the liquid crystal layer positioned to the left and right side of the data line would be arranged in an undesirable direction, causing light leakage in the region.